Medical balloon with incorporated fibers

ABSTRACT

A balloon catheter assembly comprises a balloon having attached to or in its wall one or more filar elements, extending from one end of the balloon to the other. The filar elements are made of a material which is at least as flexible as the material forming the walls of the balloon. In the event of circular burst of the balloon, the filar element(s) prevent disconnection of the material of the balloon into two or more separate pieces. The filar element(s) become attached to or in the material of the balloon wall when the raw material is inflated to the shape of a mold. The filar elements may comprise a natural fiber, a synthetic fiber or a metal wire.

CROSS-REFERENCE RELATED APPLICATIONS

This application claims priority to GB application no. 1205362.5, filedMar. 27, 2012, titled “Medical Balloon with Incorporated Fibers”, andNon-Provisional patent application Ser. No. 13/784,072 filed on Mar. 4,2013, and Non-Provisional patent application Ser. No. 14/748,907 filedon Jun. 24, 2015, the contents of which are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates generally to medical devices and moreparticularly to a balloon of a balloon catheter. The teachings hereincan be used in balloons used for numerous medical applications,including for example angioplasty, scoring or cutting, occlusion,valvuloplasty, to expand implantable medical devices and so on.

BACKGROUND ART

Balloon catheters, which generally comprise a catheter tube with aninflatable balloon at the distal end thereof, are widely used in themedical profession for various endoluminal procedures. One commonprocedure involving the use of a balloon catheter relates to angioplastydilation of coronary or other arteries suffering from stenosis (that is,a narrowing of the arterial lumen which restricts blood flow). Otherprocedures of the types mentioned above are also practiced in the art.

In all balloon catheter procedures there is a risk that the balloon mayburst, either during its inflation or during the medical procedureitself. When balloon burst occurs, only parts of the balloon whichremain attached to the catheter are easily recoverable from the site ofthe procedure by the withdrawal of the catheter. Thus, if the balloonbursts in such a way that all the balloon material remains connected ina single piece, and therefore attached to the catheter, then all of thematerial of the burst balloon is recoverable by withdrawal of thecatheter. On the other hand, if the balloon bursts in such a way thatthe balloon material becomes circumferentially disconnected into two ormore separate fragments or pieces, that is suffers a circumferentialburst, only fragments or sections of the balloon material which remainattached to the catheter are recoverable by withdrawal of the catheter.Fragments of the balloon which become disconnected from the catheter arenot so easily recovered and can require a separate medical procedure toremove them.

Current methods to address the problems resulting from circumferentialburst of medical balloons include increasing the thickness of thematerial used to form the balloon walls and providing complex balloonstructures with strengthening sleeves, braiding or meshes. While theseapproaches may reduce the chance of balloon burst, they are far fromideal solutions. For example, thickening the balloon walls orintroducing additional strengthening elements may reduce the flexibilityand compressibility of the balloon, leading to an increase in theballoon and introducer profile. This is contrary to the general desirefor as small a balloon and introducer profile as possible.

DISCLOSURE OF THE INVENTION

The present invention seeks to provide an improved medical balloon andballoon catheter assembly.

According to an aspect of the present invention, there is provided aballoon catheter assembly including: a catheter; an inflatable balloonhaving a longitudinal direction and comprising a balloon wall made fromat least one balloon material and provided with a body portion, firstand second end cones, and first and second neck portions, which neckportions are attached to the catheter; and one or more filar elementsformed of at least one filar material attached to or embedded in theballoon wall, wherein the one or more filar elements extend solely inthe longitudinal direction of the balloon from the first neck portion tothe second neck portion; wherein the one or more filar elements providea barrier to circumferential tear propagation.

The filar elements provide circumferential strengthening of the balloonalong its entire unsupported length, that is along the entire length ofthe balloon which is not fixed to and thus supported by the catheter.They provide a barrier to stop the propagation of a circumferentiallyextending tear in the balloon, thereby no prevent or substantiallyreduce the risk of the balloon tearing into separate and loosecomponents. More specifically, an advantage of this structure is that ifa circumferential balloon burst develops, the filar element or elementshalt the circumferential propagation of the tear, thus ensuring that theballoon material remains connected in a single piece and remainsattached to the catheter. In this way, the entire balloon is readilyrecoverable from the site of the procedure by withdrawal of thecatheter, even after the event of a circumferential burst.

The filar elements extend solely along the longitudinal direction of theballoon, that is there are no filar elements which extendcircumferentially around the balloon in annular manner. This allows theballoon to expand radially outwardly without any material constraintfrom the filar elements. That is to say, there are no filar elementswhich extend circumferentially around the balloon, in ring or similarformat.

In the preferred embodiment, the filar element or elements do notmaterially affect the flexibility of the balloon. In practice, the filarelements may be as flexible as the balloon wall at least in alongitudinal direction of the balloon. This leads to a structure inwhich circumferential propagation of a tear in the balloon wall ishalted, without any compromise in the ability of the balloon to expandradially outwards, and without the need for an overly complex balloonstructure or thickened balloon wall.

The filar elements thus do not materially or measurably alter theperformance of the balloon in terms of the functions intended to beperformed by the balloon. They exist solely to prevent complicationsshould the balloon burst. In particular, the filar elements have noscoring or abrading effect on a vessel wall.

In an embodiment, the filar element or elements are compressible, thatis in a direction transverse to the longitudinal. Such compressibilityminimizes the chance of the filar elements affecting the performance ofthe balloon, particularly in the case where they are positioned on thesurface of the balloon wall or only partially embedded therewith.

Preferably, the balloon wall has a thickness of between about 0.005millimeters and about 0.080 millimeters and, advantageously, the atleast one filar element has a diameter of between around 0.01millimeters and 0.05 millimeters.

The at least one filar element may be completely embedded in the balloonwall, partially embedded in the balloon wall or may even be positionedon the balloon wall, either on the outside of the balloon or on theinside thereof.

The filar element or elements may be single strand structures or may bemulti stranded. Advantageously, the at least one filar materialcomprises natural and/or synthetic fiber. The material may, forinstance, comprise as least one of: para-aramid synthetic fiber such asKevlar, ultra high molecular weight polyethylene such as Dyneema,polytetrafluoroethylene fiber such as Gore-Tex, carbon fiber, cotton andthe like.

In a practical embodiment, the filar elements have a linear density(dtex) of between 10 and 60 and are multi filamentary, each having fromaround 5 to 50 filaments per strand, preferably around 25 filaments.Each filament may have a density of around 0.5 to 2 denier (or similardtex density).

The filar elements preferably have a tensile strength of between around4 N to around 20 N. They may have an elongation at break of no more thanaround 5%.

The filar element(s) are made of a material resistive to breakage andtear and which is preferably significantly stronger than the balloonwall, thereby being strong enough to halt circumferential propagation ofa tear in the balloon wall.

In an embodiment, the balloon wall comprises an outer layer of a firstmaterial and an inner layer of a second material, wherein a softening ormelting temperature of the first material is lower than a softening ormelting temperature of the second material.

The filar element or elements are preferably at least partially embeddedin the outer layer of the balloon wall.

The filar element or elements preferably extend longitudinally, that isalong the longitudinal axis of the balloon, but may extend at an angleto the longitudinal, such as helically. The filar element or elementspreferably do not extend transversely around the circumference of theballoon in annular manner.

The size and flexibility of the filar element(s) is advantageously suchthat the properties of the balloon, for example its ability to bewrapped onto the catheter, its wall thickness and its flexibility, arenot materially affected by the provision of the filar element(s) on orin the balloon wall. This is particularly important when the balloon isfor use in more delicate applications, such as in smaller and moredelicate vessels including for instance cerebral vessels, where theoverall thickness of the balloon catheter, when the balloon is wrappedonto the catheter for endoluminal delivery, may be of the order of 1 mmor less.

The filar elements are such that they do not cause interference with ordamage to the interior surface of the lumen at the site to which theballoon is deployed. In this regard, the filar elements may becompletely embedded in the balloon wall or produce only a minorprotrusion which does not cut or score into the vessel wall. Theflexibility of the filar elements will also ensure that these do not cutor score the vessel wall.

According to another aspect of the present invention, there is provideda method of forming a balloon for a balloon catheter, including thesteps of: providing a mold; providing one or more filar elements alongthe entire length of the mold; heating a balloon material in the mold;and inflating the balloon material to the shape of the mold to form theballoon, said balloon having a longitudinal direction; wherein theheating and inflating steps attach or embed the one or more filarelements on or in the balloon wall with the one or more elementsextending solely in the longitudinal direction of the balloon.

Advantageously, the balloon material is formed by co-extruding rawmaterial to form a balloon wall comprising an outer layer of a firstmaterial and an inner layer of a second material, wherein a softening ormelting temperature of the first material is lower than a softening ormelting temperature of the second material.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are described below, by way ofexample only, with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic view of an embodiment of balloon catheterintroducer assembly;

FIG. 2 is an enlarged cross-sectional view of the distal end of aballoon catheter of FIG. 1;

FIG. 3 is a side elevational view of a balloon structure in accordancewith an embodiment of the present invention;

FIG. 4 is a schematic representation showing example positions of thefibers with respect to the balloon wall;

FIG. 5 is an exploded view of a mold in accordance with an embodiment ofthe present invention;

FIG. 6 is a cross-sectional view along line IV-IV of FIG. 5; and

FIG. 7 shows a cross-section of a part of a balloon 44 in the process ofmanufacture.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is to be understood that the drawings do not show the variouselements of the device to scale and often these are shown in enlargedform, solely for the purposes of clarity of explanation.

Referring first to FIG. 1, there is shown an embodiment of introducerapparatus 10 which is deployed endoluminally in a patient and includes acatheter 12 on which a medical balloon 18 is fitted. The structures ofthe preferred embodiments of balloon are described in further detailbelow. The combination of catheter 12 and balloon 18 is typically termeda balloon catheter.

At a proximal end of the catheter 12 there is provided an externalmanipulation and valving unit 20. The unit 20 can be of conventionalform and is therefore not described in detail herein as its componentsand structure will be readily apparent to the skilled person. Typically,the unit will include one or more ports 30, 32 for the supply or removalof fluid from the components of the apparatus 10, such as inflationfluid for the balloon 18 and flushing fluid into the assembly.

The balloon 18 is typically fitted into the introducer apparatus 10 in adeflated and wrapped condition, in which it has a small diameter, and iscovered by a sheath (not shown). Upon location of the distal end of theassembly 10 at the site to be treated, the sheath is retracted to exposethe balloon 18 and then the balloon 18 is inflated so as to adopt theshape shown for example in FIGS. 2 and 3.

FIG. 2 shows an enlarged view of a typical balloon catheter and balloon18 in longitudinal cross section. The balloon 18 normally has agenerally circular cylindrical form and is secured at its ends to thecatheter 12. The balloon 18 may be made of a thermoformable,substantially non-compliant material such as polyether block amide (suchas Pebax), polyamide (such as Nylon 12), polyethylene, PET orpolyurethane. The balloon may be formed from a co extrusion of differentlayers or blend of more than one of these materials.

As used herein, the term thermoformable refers in general to a materialthat may be shaped under conditions of temperature and/or pressure.Preferably, the thermoformable polymer is stretchable or formable, insome instances flowable, above a certain processing temperature, buttakes a set form having desired resilience and strength properties at atemperature of intended use (such as room temperature to bodytemperature).

The balloon 18 is inflatable and thus impermeable or substantiallyimpermeable, as well as being capable of being wrapped or folded to arelatively small diameter for endoluminal delivery.

When the balloon 18 is used to deploy a medical device, in practice themedical device is fitted over the balloon 18 when the latter is in adeflated and wrapped configuration on the catheter 12, in known manner.

In this embodiment, the balloon 18 has a substantially cylindrical bodyportion 34 and first and second end cones 36, 38 each bounded by arespective neck portion 40, 42. The portions 34 to 42 of the balloon 18are typically formed by heating and inflation of a raw tubing in asuitable mold, as is described in more detail below. This heating andinflation forms the end cones 36, 38 as well as the body portion 34.Neck portions 40, 42 may be the unstretched raw tubing but may also beformed by radially compressing the end portions of the raw tubing duringthe heating and inflation process.

The balloon 18 is fixed or bonded to the catheter 12 at the neckportions 40, 42 of the balloon 18.

In general, it is preferred that the balloon 18 has relatively thinwalls, as wall thickness affects the size (diameter) of the balloon whenfolded or wrapped as well as its flexibility. However, it is typical ofprior art balloons that the end cones 36, 38 have walls which arethicker than the walls of the body portion 34 as a result of the balloonforming process. Specifically, the end cone portions 36, 38 willtypically have a wall thickness which increases in the direction ofnarrowing of the taper, as a result of the lesser amount by which theseportions expand during formation of the balloons.

FIG. 3 shows a balloon 44 in accordance with an embodiment of thepresent invention. As with the balloon 18 shown in FIG. 2, the balloon44 has in this example a cylindrical body portion 34 and first andsecond end cones 36, 38 each bounded by a respective neck portion 40,42.

The wall of the balloon 44 may be a single layer or of a plurality oflayers, preferably two layers of material which are coextruded andintegral with one another. In the case that the balloon has two or morelayers, the outer layer may be of a material having a softening ormelting temperature which is lower than the softening or meltingtemperature of the material of the inner, underlying, layer. The wall ofthe balloon 44 could equally be formed of three of more layers. It is tobe understood that the outer layer could be formed of a material whichbecomes more flowable than the inner layer of the balloon at theproduction temperatures used.

The thickness of the balloon wall is preferably between around 0.005millimeters to around 0.08 millimeters, typically for a balloon havingan inflated diameter of around 1.5 millimeters to around 36 millimeters.

The balloon 44 contains one of more filar elements 46, which areattached to or incorporated in the outer layer of the balloon structure44. The purpose of the filar elements 46 is to halt the circumferentialpropagation of a tear in the balloon wall. These filar elements arestrong but are thin and/or flexible so as not to affect adversely theproperties of the balloon, in particular balloon flexibility andwrappability.

The balloon 44 of FIG. 3 has four sets of filar elements 46 extendingalong the length of the balloon, only two being visible in the view ofFIG. 3. It is to be understood, though, that a different number of filarelements 46 may be used and in some instances there may be just a singlefilar element 46, while in other embodiments there may be two, three ormore than four.

The filar elements 46 may be at least as flexible as the balloon walland in some instances may be more flexible than the balloon wall. Moreparticularly, the filar elements 46 may be at least as flexible as theballoon wall at least in a longitudinal direction of the balloon. Inparticular, the filar elements 46 are not intended to affect the normalcharacteristics or properties of the balloon 44, allowing the balloon toperform in the same manner as a balloon of similar structure but with nofilar elements, especially to provide no scraping or scoring effectwhatsoever to the balloon. In the preferred embodiment, the filarelements are compressible in a direction transverse to their length,having a hardness of no more than a hardness of the balloon wall,preferably less than that of the balloon wall.

Thus, in the preferred embodiment, the filar elements 46 do notmaterially affect the flexibility of the balloon. In practice, the filarelements 46 may be as flexible as the balloon wall at least in alongitudinal direction of the balloon. This leads to a structure inwhich circumferential propagation of a tear in the balloon wall ishalted, without any compromise in the ability of the balloon to expandradially outwards, and without the need for an overly complex balloonstructure or thickened balloon wall.

The at least one filar element 46 advantageously has a diameter ofbetween around 0.01 millimeters and 0.05 millimeters.

The filar elements are formed of a material which is different from thematerial or materials of the balloon wall and could be formed as asingle strand of material but in preferred embodiments are formed as amulti-stranded material. They may be made of natural or synthetic fiberor a combination of the two. Suitable materials include para-aramidsynthetic fiber such as Kevlar, ultra high molecular weight polyethylenesuch as Dyneema, polytetrafluoroethylene fiber such as Gore-Tex, carbonfiber, cotton and the like. It is to be understood that the filarelements 46 may be made of a plurality or mix of these filar materials.

In the preferred embodiment, the filar elements have a linear density(dtex) of between 10 and 60 and are multi filamentary, each having fromaround 5 to 50 strands per element, most preferably around 25 strands.Each strand of the multi filament element may have a density of around0.5 to 2 denier (or similar dtex density). The use of multi-filamentelements provides a number of advantages. First, the elements arecompressible in bulk, primarily by allowing sliding of the fibers orstrands over one another, which results in increased compressibility.Secondly, the fibers can be made of a material of high tensile strengthcompared to the balloon yet without adversely affecting the longitudinalflexibility of the balloon.

Thirdly, the multi stranded filaments can minimize, particularly avoid,any surface differences or performance differences to the ballooncompared to an equivalent balloon without such filar elements. Fourthly,these features allow for the use of materials which are significantlystronger than the balloon without affecting the performancecharacteristics of the balloon. Other advantages will become apparent tothe skilled person.

The filar elements preferably have a tensile strength of between around4 N to around 20 N. They may have an elongation at break of no more thanaround 5%. In other words, the filar elements have a substantial tensilestrength with little elongation prior to breakage, which optimizes theirqualities for stopping tear propagation.

Each filar element 46 extends longitudinally between the two ends of theballoon 44, preferably substantially parallel to the longitudinal axis48 of the balloon structure 44. The filar elements 46 extend through theend cones 36, 38 and neck portions 40, 42, and extend all the way to thedistal and proximal ends of the balloon 44. As such, the filar elements46 act as strengthening elements for interconnecting the entire lengthof the balloon 44, that is to say filar elements 46 serve to connectboth ends of the balloon 44 in a continuous manner such that all pointsalong the length of the balloon 44 are attached to the filar element 46at some location around the circumference of the balloon 44. In thepreferred embodiment there are no filar elements 46 which extendcircumferentially around the balloon 44, that is as annular rings aroundthe balloon.

In the embodiment shown in FIG. 3, the filar elements 46 extend throughthe conical end portions and through the necks to the extremities of theballoon, that is for the entire extent of the balloon 44. It is notessential that the filar elements 46 extend all the way to the veryextremities of the balloon. It is, however, important that the fibersextend from the body portion past the point where the balloon is fixedor bonded to the catheter and terminate in the region in which theballoon is fixed or bonded to the catheter. In the arrangement of FIG.3, this means that the filar elements 46 may extend from the bodyportion 34 past the point where the end cones 36, 38 join the respectiveneck portions 40, 42, and terminate in the regions of the two neckportions 40, 42 but before the very ends of the balloon. For the sake ofease of manufacture, though, t is preferred that the filar elementsextend for the entire length of the balloon.

The filar elements 46 are preferably embedded in the balloon material,advantageously in an outer layer of the balloon. Various examples of theposition of the filar elements 46 with respect to a balloon wall 50 areshown in FIG. 4. It is to be appreciated that in an embodiment theballoon has two layers and thus that FIG. 4 shows only the outer layer.In position “A”, the filar elements 46 are completely embedded in theouter layer of the balloon wall 50, such that there is no protrusionfrom the outer surface 52 of the balloon. In position “B”, the filarelements 46 are again completely embedded in the balloon wall 50 suchthat there is no protrusion from the outer surface 52 of the balloon,although the filar elements 46 are located proximate the outer surface52 of the balloon. In position “C”, the filar elements 46 are partiallyembedded in the balloon wall 50 such that a portion of each fiber 46protrudes from the outer surface 52 of the balloon. In position “D”, thefilar elements 46 are partially embedded in the balloon wall 50 suchthat a portion of each filar elements 46 protrudes from the outersurface 52 of the balloon. The protruding portion of the filar elements46 is greater in position “D” than in position “C”. The filar elements46 may even be positioned on the surface of the balloon 44, either onthe outer surface or on the inner surface.

In the examples in which the filar elements protrude from the outersurface of the balloon, either the degree of this protrusion is smallenough, or the filar elements are flexible enough, that their presencedoes not affect the function of the balloon. In the preferredembodiments, the filar elements have no noticeable or measurable effecton the characteristics of the balloon 44.

The materials of the filar elements 46, such as those disclosed herein,has a high tensile strength to as not to rupture should the balloon walltear. Yet, they are sufficiently flexible not to materially affect theflexibility of the balloon. Moreover, by being attached to or embeddedin the balloon wall, the filar elements 46 will wrap with the balloonfor delivery and subsequent deployment. The nature of the filar elementswill have no effect on the wrappability of the balloon.

The raw tubing used for the manufacture of the balloons taught herein isadvantageously a continuous length of tubing having a substantiallycircular cylindrical tube portion.

FIGS. 5 and 6 show an embodiment of apparatus used to mold such rawtubing into the required balloon form. As can be seen in FIG. 5, themold 60 comprises a central body section 62 and two end caps 64, 66. Thecentral body section 62 forms the body portion of the balloon, and theend caps 64, 66 form the respective end cones of the balloon. The endcaps 64, 66, which may themselves be in a plurality of parts which canbe disassembled, that is can be removed from the central section 62 forremoval of the formed balloon from within the mold 60.

Prior to molding, one or more filar elements 46 are located through themold 60, extending beyond the end caps 64, 66 of the mold 60. The rawtubing is fed into the mold from an end port and then inflated in themold 60 under heat so as to stretch the central part of the raw tubingto form the body portion and end cones of the balloon, while the ends ofthe raw tubing are held radially compressed so as not to inflate, thusforming the neck portions of the balloon. After the balloon has beenformed in this way, the balloon is cooled and then removed from themold.

The inflation of raw tubing 70 in the mold 60 is shown diagrammaticallyin FIG. 6. The raw tubing 70 expands in the direction of the arrows 72towards the inner surface of the mold 60, in so doing pushing the filarelements 46 towards the inner surface of the mold. When the raw tubing70 is fully expanded with the filar elements 46 unable to move further,being bounded by the mold wall, they become at least partially embeddedinto the outer layer 74 of the balloon, which will have been heated atleast to a softening or flowing temperature.

As described above, the preferred embodiment has a balloon formed of twolayers, with the inner layer becoming less flowable than the outer layerduring the balloon formation process. The filar elements 46 willtherefore become embedded in the outer layer but not the inner layer ofthe balloon.

Subsequent cooling of the mold will cause cooling and then setting ofthe balloon, which can then be removed with the filar elements attached.

In FIG. 5 four filar elements 46 are located in the mold, and thus fourfilar elements 46 will extend generally linearly along the outer surfaceof the balloon. In practice, however, there may be provided a differentnumber of filar elements 46 such as one, two, three or more than four.

Referring to FIG. 7, there is shown a cross-sectional schematic view ofan example of mold with a balloon in the process of being formed. Themold has a mold wall 60 which supports the raw tubing on inflation, tothe shape of the final balloon 44. In this embodiment the balloon 44 isformed of two layers, an outer layer 80 of a reflow material, ormaterial with a lower softening temperature, and an inner layer 82 of amaterial having a higher softening temperature. The filar element 46becomes embedded in the balloon, specifically within the outer layer 80.The inner layer 82 acts as a support layer, not only to the filarelements 46 but also to the outer player 80. Even though in the mild,the thickness of the filar elements 46 may cause the inner layer 82 tocurve slightly around the filar elements 46, this will not be exhibitedduring later use of the balloon 44. As explained above, the filarelements 46 are flexible enough, and in some cases at least compressibleenough, not to have any material effect on the characteristics orperformance of the balloon 44.

In another embodiment, the balloon may be formed as a single layer, inwhich case the filar elements 46 will become embedded in the singlelayer of the balloon wall.

Other elements could be incorporated into the balloon structure inaddition to the filar elements, depending on the intended purpose of theresulting balloon catheter. For example, one or more scoring elementscould be disposed on the balloon.

Although the filar elements have been described as extendingsubstantially linearly along the longitudinal direction of the balloon,this is not essential. They could extend at an angle thereto. Theycould, for example, wind around the balloon in a helical manner.

All optional and preferred features and modifications of the describedembodiments and dependent claims are usable in all aspects of theinvention taught herein. Furthermore, the individual features of thedependent claims, as well as all optional and preferred features andmodifications of the described embodiments are combinable andinterchangeable with one another.

What is claimed is:
 1. A balloon catheter assembly, comprising: acatheter; an inflatable balloon having a longitudinal direction andcomprising a balloon wall made from at least one balloon material andprovided with a body portion, first and second end cones, and first andsecond neck portions, which neck portions are attached to the catheter,the balloon material having only two layers, an outer layer of a firstmaterial and an inner layer of a second material, wherein a softening ormelting temperature of the first material is lower than a softening ormelting temperature of the second material; and, one or more filarelements at least partially embedded in the outer layer but not theinner layer, wherein the one or more filar elements extend solely in thelongitudinal direction of the balloon from the first neck portion to thesecond neck portion, and there are no filar elements that extendcircumferentially around the balloon in an annular manner when theballoon is configured for delivery and subsequent deployment, andwherein the one or more filar elements are at least as flexible in alongitudinal direction as the balloon wall.
 2. An assembly according toclaim 1, wherein the one or more filar elements are at least as flexibleas the balloon wall.
 3. An assembly according to claim 1, wherein theone or more filar elements provide no material scoring or abradingfunction.
 4. An assembly according to claim 1, wherein the one or morefilar element or elements are compressible.
 5. An assembly according toclaim 1, wherein the balloon wall has a thickness of between about 0.005millimeters and about 0.080 millimeters.
 6. An assembly according toclaim 1, wherein the one or more filar element has a diameter of betweenaround 0.04 millimeters and 0.05 millimeters.
 7. An assembly accordingto claim 1, wherein the one or more filar element has a linear density(dtex) of between 40 and
 60. 8. An assembly according to claim 1,wherein the one or more filar element is multi-filamentary, each havingfrom around 5 to 50 strands per element.
 9. An assembly according toclaim 8, wherein the one or more filar element has around 25 strands.10. An assembly according to claim 8, wherein each strand has a densityof around 0.5 to 2 denier.
 11. An assembly according to claim 1, whereinthe one or more filar element has a tensile strength of between around4N to around 20N.
 12. An assembly according to claim 1, wherein the oneor more filar element exhibits an elongation at break of no more thanaround 5%.
 13. An assembly according to claim 1, wherein the one or morefilar element is at least one of: completely embedded in the balloonwall and partially embedded in the balloon wall.
 14. An assemblyaccording to claim 1, wherein the one or more filar material comprisesnatural and/or synthetic fiber.
 15. An assembly according to claim 14,wherein the one or more filar material comprises as least one of:para-aramid synthetic fiber, ultra-high molecular weight polyethylene,polytetrafluoroethylene fiber, carbon fiber, and cotton.